Researchers at the University of Eastern Finland studied the effects of long-term heavy alcohol use in adolescence and found it altered certain brain functions.

The study, the first of its kind to analyze long-term effects of alcohol in adolescents, found that heavy alcohol use can alter the cortical excitability and functional connectivity in the adolescent brain. The research was part of the Adolescents and Alcohol Study.

The changes in the brain occurred in otherwise healthy adolescents who were heavy alcohol users but did not fit the criteria for a substance abuse disorder.

Researchers followed 27 adolescents starting at age 13 to 18 years old who were heavy drinkers throughout their teen years and 25 controls who were of the same age, gender and education level who reported little to no alcohol use.

Participants’ brain activity was analyzed at age 23 to 28 using transcranial magnetic stimulation, or TMS, and simultaneous electroencephalogram, or EEG. These tests show how different regions of the cortex react to electrical stimulation and identify the functional connectivities between regions.

Researchers found that the cortical response to the TMS pulse was stronger and there was greater overall electrical activity in the cortex and greater activity of the gamma-aminobutyric acid, or GABA, neurotransmission system of heavy alcohol users. Results also showed differences in how this activity spread throughout different regions of the brain.

GABA is a vital neurotransmitter that inhibits brain and central nervous system function and may cause anxiety, depression and the pathogenesis of numerous neurological disorders.

Researchers found that heavy alcohol use causes alterations in the electrical and chemical neurotransmission in study participants.

Earlier studies have shown the detrimental effects of heavy alcohol use in adolescence alters the function of the GABA neurotransmission system and causes cortical thinning, all among adolescents who did not meet the criteria for having a substance abuse disorder.

These results have researchers questioning the diagnostic criteria for substance abuse disorders and if it should be altered for adolescents.

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